Re: [PATCH v7] overlayfs: Provide a mount option "volatile" to skip sync

[Vivek Goyal <vgoyal@redhat.com>]

On Tue, Sep 01, 2020 at 11:22:26AM +0300, Amir Goldstein wrote:
[..]
> 
> > +       int nr_elems = ARRAY_SIZE(dirty_path);
> > +
> > +       err = 0;
> > +       parent = ofs->workbasedir;
> > +       dget(parent);
> > +
> > +       for (i = 0; i < nr_elems; i++) {
> > +               name = dirty_path[i];
> > +               len = strlen(name);
> > +               inode_lock_nested(parent->d_inode, I_MUTEX_PARENT);
> > +               child = lookup_one_len(name, parent, len);
> > +               if (IS_ERR(child)) {
> > +                       err = PTR_ERR(child);
> > +                       goto out_unlock;
> > +               }
> > +
> > +               if (!child->d_inode) {
> > +                       unsigned short ftype;
> > +
> > +                       ftype = (i == (nr_elems - 1)) ? S_IFREG : S_IFDIR;
> > +                       child = ovl_create_real(parent->d_inode, child,
> > +                                               OVL_CATTR(ftype | 0));
> > +                       if (IS_ERR(child)) {
> > +                               err = PTR_ERR(child);
> > +                               goto out_unlock;
> > +                       }
> > +               }
> > +
> > +               inode_unlock(parent->d_inode);
> > +               dput(parent);
> > +               parent = child;
> > +               child = NULL;
> > +       }
> > +
> > +       dput(parent);
> > +       return err;
> > +
> > +out_unlock:
> > +       inode_unlock(parent->d_inode);
> > +       dput(parent);
> > +       return err;
> > +}
> > +
> 
> I think a helper ovl_test_create() along the lines of the helper found on
> my ovl-features branch could make this code a lot easier to follow.
> Note that the helper in that branch in not ready to be cherry-picked
> as is - it needs changes, so take it or leave it.

Hi Amir,

For now, I will like to stick with it. You can change it down then line
once ovl_test_create() is ready to be merged.

Vivek